Product Description: Glassine is a semi-transparent material similar to waxed paper without the wax. These envelopes are open at the top and have a flap along the top, there are no adhesives on the flap they may come in a square or triangle flap. They can be used for Storing stamps, blocks, sheetlets, stamp booklets, paper money, coins, FDC's, postcards, telephone cards, photos, negatives, and wedding favors.